Not many people were indifferent to Roger Ebert. Many people loved him, some hated him. The ones who hated him primarily felt that he demeaned film criticism, which is not inaccurate but depends on a fairly stuffy definition of that profession. As half of the thumbs up/thumbs down TV team of Siskel and Ebert, he spent decades bickering with fellow Chicago writer Gene Siskel about the merits of films from My Dinner with Andre to Benji the Hunted.

The number of people who loved him grew in the last years of his life, as he faced the cancer that took away his ability to eat, drink and speak with stubborn openness, increasing his writing output and including himself as a subject.

Life Itself takes its title and some narration from Ebert’s 2011 memoir. (The narration is read in the film by someone named Steven Stanton, which I only know from scanning the end credits: he sounds so much like Ebert that it’s a bit disturbing, especially as he talks about being unable to speak.) It covers most of his life story, from pampered only child though his early career as a hard-drinking newspaperman (a cliché he adopted and embraced until he went on the wagon in 1979). It touches on his tangent into scriptwriting for Russ Meyer (though it ignores that Ebert wrote several other films for the man affectionately known in the film biz as “King Leer.”)

And of course it offers lots of clips of him sparring with Siskel, which are funny—unexpectedly so in that they often make Ebert look like the goat. (The sidelines into Siskel’s biography are surprising as well.)

But the most compelling parts of this film by Steve James (whose three-hour basketball documentary Hoop Dreams was championed by Ebert) follow the writer in what neither of them knew at the time were the final months of his life. These scenes are touching in their depiction of a man enjoying the love of his family, but they can also be tough to watch: he insisted that the camera be spared nothing, under the theory that a movie about invasive cancer should depict it as it is. You’ve probably seen photos of Ebert after the operation that took away his jaw, but that’s nothing like seeing him on film. Is this going too far? I don’t think so. The film opens with a clip of Ebert describing cinema as “a machine that generates empathy,” and there’s no better example than this final testament.

Opens Friday at the Amherst Theater.

Watch the trailer for Life Itself